[Bug middle-end/27529] New: Does not fold (char *)(size_t)char_ptr or (size_t)(char *)size_t_var

[Bug middle-end/27529] New: Does not fold (char *)(size_t)char_ptr or (size_t)(char *)size_t_var

[rguenth at gcc dot gnu dot org]

Fold does not fold two comparisons in a row if the intermediate type differs
in being a pointer vs. an integer variable.  This also is the reason for not
folding (Foo *)(char *)foo with foo being of Foo& type (we can fold that to
(Foo *)foo).

There's code to do that I think, but it's just missing adjustment for pointers:

          /* In addition to the cases of two conversions in a row
             handled below, if we are converting something to its own
             type via an object of identical or wider precision, neither
             conversion is needed.  */
          if (TYPE_MAIN_VARIANT (inside_type) == TYPE_MAIN_VARIANT (type)
              && ((inter_int && final_int)
                  || (inter_float && final_float))
              && inter_prec >= final_prec)
            return fold_build1 (code, type, TREE_OPERAND (op0, 0));

I have a patch.  Of course RTL doesn't care.


-- 
           Summary: Does not fold (char *)(size_t)char_ptr or (size_t)(char
                    *)size_t_var
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Keywords: missed-optimization, TREE
          Severity: enhancement
          Priority: P3
         Component: middle-end
        AssignedTo: rguenth at gcc dot gnu dot org
        ReportedBy: rguenth at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27529

[Bug middle-end/27529] Does not fold (char *)(size_t)char_ptr or (size_t)(char *)size_t_var

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2006-05-10 15:47 -------
Confirmed.


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pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pinskia at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2006-05-10 15:47:38
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27529

[Bug middle-end/27529] Does not fold (char *)(size_t)char_ptr or (size_t)(char *)size_t_var

[rguenth at gcc dot gnu dot org]

------- Comment #2 from rguenth at gcc dot gnu dot org  2006-05-11 08:30 -------
Subject: Bug 27529

Author: rguenth
Date: Thu May 11 08:29:40 2006
New Revision: 113692

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=113692
Log:
2006-05-11  Richard Guenther  <rguenther@suse.de>

        PR middle-end/27529
        * fold-const.c (fold_unary): Handle intermediate conversion
        to a pointer type like intermediate conversion to an integer
        type in folding of (T1)(T2)var to var.
        Match the code to the comment in the final conversion for
        (T1)(T2)var to (T1)var regarding to type precision.  Rather
        than disallow T1 being of pointer type, assert that both T1
        and var are of pointer type or not.  Make sure not to fall
        over the frontends lazyness wrt array to pointer decay though.

        * gcc.dg/tree-ssa/foldcast-1.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/foldcast-1.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/fold-const.c
    trunk/gcc/testsuite/ChangeLog


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27529

[Bug middle-end/27529] Does not fold (char *)(size_t)char_ptr or (size_t)(char *)size_t_var

[rguenth at gcc dot gnu dot org]

------- Comment #3 from rguenth at gcc dot gnu dot org  2006-05-11 08:30 -------
Fixed.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.2.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27529

[Bug middle-end/27529] Does not fold (char *)(size_t)char_ptr or (size_t)(char *)size_t_var

[patchapp at dberlin dot org]

------- Comment #4 from patchapp at dberlin dot org  2006-05-15 19:39 -------
Subject: Bug number PR27529

A patch for this bug has been added to the patch tracker.
The mailing list url for the patch is
http://gcc.gnu.org/ml/gcc-patches/2006-05/msg00415.html


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27529